arc: Restore Arc OptIn notification.

chrome/browser/chromeos/arc/arc_auth_notification.h

Index: chrome/browser/chromeos/arc/arc_auth_notification.h
diff --git a/chrome/browser/chromeos/arc/arc_auth_notification.h b/chrome/browser/chromeos/arc/arc_auth_notification.h
new file mode 100644
index 0000000000000000000000000000000000000000..76e47bba02898d6758f5f096060ce6f29b3b2025
--- /dev/null
+++ b/chrome/browser/chromeos/arc/arc_auth_notification.h
@@ -0,0 +1,21 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_CHROMEOS_ARC_ARC_AUTH_NOTIFICATION_H_
+#define CHROME_BROWSER_CHROMEOS_ARC_ARC_AUTH_NOTIFICATION_H_
+
+class Profile;
+
+namespace arc {
+
+// First run notification that can enable Arc.
+class ArcAuthNotification {
+ public:
+  static void Show(Profile* profile);
+  static void Hide();
+};
+
+}  // namespace arc
+
+#endif  // CHROME_BROWSER_CHROMEOS_ARC_ARC_AUTH_NOTIFICATION_H_